set default value for combo in subform accord. to form combo (company/job)

[hjgwright]

Hi.
I've got a form with Job details.
This form has two subforms - Companies related to Job, and Record of Conversations with Employees.
I've just updated the Record of Conversations with Employees form to include the Job relevant to the employee, but it keeps asking me to fill in the Role_ID or I can't go on (Role_ID eg architect, client etc).
I want to autopopulate the Role_ID using the data from the tables, according to the Company and Job so that it has a default value and I don't have to enter it (it will become a mess).

Thanks,
HW